[PATCH v2 28/29] misc: add power sequencing driver for initializing StarFive peripherals

[Ahmad Fatoum]

There will likely not be a use case for having neural network
accelerator driver support within barebox. Still the driver requires a
reset sequence, which is not yet supported by vendor kernel's or known
forks. Until Linux can take care of this itself, add a simple driver
that gets some of the peripherals out of reset.

There also enables unconditionally some of the clocks that the vendor
kernel may depend on. Hopefully, in future, the whole driver can be
dropped when the kernel starts to do clock and reset control itself.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 drivers/misc/Kconfig           | 10 ++++
 drivers/misc/Makefile          |  1 +
 drivers/misc/starfive-pwrseq.c | 92 ++++++++++++++++++++++++++++++++++
 3 files changed, 103 insertions(+)
 create mode 100644 drivers/misc/starfive-pwrseq.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 87674a2a29f9..7426dfc46398 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -42,4 +42,14 @@ config ACPI_TEST
 	help
 	  This is a simple Test driver to test the ACPI bus.
 
+config STARFIVE_PWRSEQ
+	bool "StarFive power sequencing driver"
+	depends on SOC_STARFIVE
+	help
+	  This driver sets up a number of StarFive peripherals not matched
+	  by more specific barebox drivers by deasserting reset lines, muxing
+	  pins and/or enabling clocks. Peripherals set up by this can then
+	  be accessed over /dev/mem or used from kernels which still depend
+	  on bootloader for initialization.
+
 endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 4d92465a1e5e..36743e6ae6a3 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_STATE_DRV)		+= state.o
 obj-$(CONFIG_DEV_MEM)		+= mem.o
 obj-$(CONFIG_UBOOTVAR)		+= ubootvar.o
 obj-$(CONFIG_ACPI_TEST)		+= acpi-test.o
+obj-$(CONFIG_STARFIVE_PWRSEQ)	+= starfive-pwrseq.o
diff --git a/drivers/misc/starfive-pwrseq.c b/drivers/misc/starfive-pwrseq.c
new file mode 100644
index 000000000000..6236547bc568
--- /dev/null
+++ b/drivers/misc/starfive-pwrseq.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Ahmad Fatoum, Pengutronix
+ */
+
+#include <driver.h>
+#include <init.h>
+#include <linux/reset.h>
+#include <dt-bindings/clock/starfive-jh7100.h>
+#include <linux/clk.h>
+
+struct starfive_pwrseq {
+	const char **names;
+};
+
+static int starfive_pwrseq_probe(struct device_d *dev)
+{
+	int ret;
+
+	ret = device_reset_all(dev);
+	if (ret)
+		return ret;
+
+	return of_platform_populate(dev->device_node, NULL, dev);
+}
+
+static struct of_device_id starfive_pwrseq_dt_ids[] = {
+	{ .compatible = "starfive,axi-dma" },
+	{ .compatible = "cm,cm521-vpu" },
+	{ .compatible = "starfive,vic-sec" },
+	{ .compatible = "sfc,tempsensor" },
+	{ .compatible = "cm,codaj12-jpu-1" },
+	{ .compatible = "cdns,xrp" },
+	{ .compatible = "starfive,nne50" },
+	{ .compatible = "nvidia,nvdla_os_initial" },
+	{ .compatible = "starfive,spi2ahb" },
+	{ /* sentinel */ }
+};
+
+static struct driver_d starfive_pwrseq_driver = {
+	.name	= "starfive_pwrseq",
+	.probe	= starfive_pwrseq_probe,
+	.of_compatible = starfive_pwrseq_dt_ids,
+};
+
+static const int clks[] = {
+	CLK_VDEC_AXI, CLK_VDECBRG_MAIN, CLK_VDEC_BCLK, CLK_VDEC_CCLK, CLK_VDEC_APB,
+	CLK_JPEG_AXI, CLK_JPEG_CCLK, CLK_JPEG_APB,
+	CLK_DLA_AXI, CLK_DLANOC_AXI, CLK_DLA_APB, CLK_NNENOC_AXI, CLK_DLASLV_AXI,
+	CLK_VENC_AXI, CLK_VENCBRG_MAIN, CLK_VENC_BCLK, CLK_VENC_CCLK, CLK_VENC_APB,
+	CLK_SGDMA1P_AXI,
+	CLK_DMA2PNOC_AXI, CLK_SGDMA2P_AXI, CLK_SGDMA2P_AHB,
+	CLK_SDIO0_AHB,
+	CLK_SDIO1_AHB,
+	CLK_SPI2AHB_AHB, CLK_SPI2AHB_CORE,
+	CLK_EZMASTER_AHB,
+	CLK_SEC_AHB, CLK_AES, CLK_SHA, CLK_PKA,
+	CLK_UART0_APB, CLK_UART0_CORE,
+	CLK_UART1_APB, CLK_UART1_CORE,
+	CLK_UART2_APB, CLK_UART2_CORE,
+	CLK_UART3_APB, CLK_UART3_CORE,
+	CLK_SPI0_APB, CLK_SPI0_CORE,
+	CLK_SPI1_APB, CLK_SPI1_CORE,
+	CLK_SPI2_APB, CLK_SPI2_CORE,
+	CLK_SPI3_APB, CLK_SPI3_CORE,
+	CLK_I2C0_APB, CLK_I2C0_CORE,
+	CLK_I2C1_APB, CLK_I2C1_CORE,
+	CLK_I2C2_APB, CLK_I2C2_CORE,
+	CLK_I2C3_APB, CLK_I2C3_CORE,
+	CLK_VP6INTC_APB,
+	CLK_TEMP_APB, CLK_TEMP_SENSE,
+
+	CLK_END
+};
+
+static int __init starfive_pwrseq_driver_register(void)
+{
+	struct of_phandle_args clkspec;
+	int i;
+
+	clkspec.args_count = 1;
+	clkspec.np = of_find_compatible_node(NULL, NULL, "starfive,jh7100-clkgen");
+	if (clkspec.np) {
+		for (i = 0; clks[i] != CLK_END; i++) {
+			clkspec.args[0] = clks[i];
+			clk_enable(of_clk_get_from_provider(&clkspec));
+		}
+	}
+
+	return platform_driver_register(&starfive_pwrseq_driver);
+}
+device_initcall(starfive_pwrseq_driver_register);
-- 
2.29.2